1. Field of the Invention
This invention relates to a machine for cutting vegetable material, such as a mowing or chopping machine, which machine comprises at least one rotatable tool carrier and tools, which are pivotally mounted on said tool carrier by means of pins which are parallel to the axis of rotation of the tool carrier.
2. Description of the Prior Art
Because the tools are pivoted, they can yield to a hard object, such as a stone, on which they impinge, and severe damage to the tools is thus prevented. In the known machines the tools are pivoted on pins which are firmly screwed into the tool carrier so that for a replacement of tools the pins must be loosened and subsequently tightened by means of a wrench or another suitable tool and that operation requires a substantial amount of work, particularly because the rough usage in agriculture may often result in a clamping and soiling of the pins. The tools used in such machines usually consist of knives of various types. But the tool carrier may also be provided with air vanes, which may constitute cutters, if desired, and such tool carrier might precede a second tool carrier, which is provided with knives. In that case any crop material lying on the ground may be sucked up and precut by the preceding tool carrier.
Published German Patent Application 24 48 130 discloses a cutting mechanism comprising a knife carrier, which consists of two thin disks, one of which is provided with fixedly mounted pins for fixing the knives. But in that mechanism the two disks must be forced apart by hand when the knives are to be fitted on the pins. The disks are subsequently released to permit the pins to snap into holes formed in the other disk. That operation can be performed without a need for a tool but the tool carrier must consist of very thin, flexible disks and the knife blades must be very thin too if said assembling operation is to be permitted. It will be understood that such a design cannot be adopted for heavy-duty mowing and chopping machines such as are usually employed in agriculture.
Published German Patent Application 32 45 617 discloses a mowing apparatus in which knives are pivoted on pins which are retained by spring force in respective seats formed in the tool carrier. For a detaching or replacement of a knife it will be necessary to pull a leaf spring from associated retaining means or the pin must axially be displaced against the force of a coil spring to such an extent that the knife is released. The design which is required for that purpose is relatively complicated and expensive and has the further disadvantage that only a single knife rather than two or more knives can be pivoted to each pin because the spring excursion would be excessively large otherwise.